Warmth itself is cheap if you accept clothes that are a bit heavier and maybe not ultra-breathable. Adding a pair of cotton long johns and a cotton long sleeve turtleneck underneath whatever you are wearing can easily keep you warm, it's just not super comfortable and not super fashionable.
I tend to wear wool long johns from December to March. Decades of experience with cotton, too. Wool is much, much better.
It's a well known thing among mountain walkers/climbers. Cotton kills.
However, the post is suggesting people in comfortable status quos change their behavior - the OP is explaining that yes, it's totally achievable to be comfortably warm in all activities indoors and out, but it costs money.
Layers are also a must if you do outdoor winter activities. You want to remove layers when you're active so you don't get all sweaty, and put them back on when you rest. Because sweat + cold wind is a really nasty combo.
Having said that, as far as I can tell most people in the city here don't do much winter sports and just own like 3 different coats for different weather.
when I'm going out for a while in the winter, I like to wear a cotton shirt, a wool sweater, insulated vest, a medium-weight windproof jacket, and a mostly empty backpack. if I get too warm, the vest and possibly the sweater can just go in the backpack. with this setup, I can be comfortable at any temperature from 30F to 60F without having to hold onto anything I'm not wearing. on really cold days, I swap in my heavy winter coat.
I know because that's what I use regularly for long walks and even bike trips
In London I had one jacket, mostly to protect against rain, but it was also an extra layer.
In Copenhagen, which has similar winter temperatures to Berlin, I had to buy a thicker jacket for the winter. I've worn the new jacket on trips to London and felt hot.
-20°F (-30°C) is a real change in perspective of what cold is. You absolutely need layering, as the equipment you need to be comfortable outside is way more than a jacket.
[1] - Outdoor Research - https://outdoorresearch.com [2] - Patagonia - https://patagonia.com [3] - Arc'teryx - https://arcteryx.com
And as others have mentioned, it's all about layering!
Look for companies that are long standing and have good warranties. These companies have good reputations to protect, and are aware that buyers of outdoor gear tend to be very loyal to companies that treat them well. My family personally swore off Columbia after two of their coats failed us catastrophically, for example.
They may be odor resistant, but for me they still get smelly after two or three days. A lot better than cotton, but not odor free.
The downsides are that even their lightest fabrics are too warm for summer, and the fabric is a lot less mechanically sturdy as cotton. It seems to tear easily. Most of my older icebreaker shirts have a few holes, even though the fabric still looks like new.
I'm also in Berlin and I use Uniqlo's HeatTech undershirt and long johns under jeans/shirt. They're pretty cheap (€10 each) and it makes a lot of difference. I never feel cold. A good jacket is also essential. Downfeather Jackets are my favourite.
Other than that it's just a hoodie between shirt and jacket, scarfs and "hand-shoes". The Coronavirus mask also helps during windy days.
I smiled reading that literal translation of "handschuhe" <3
I would recommend having a look at https://varusteleka.com, they're the biggest outdoor/surplus store in Europe, and they ship just about anywhere. Their wool flannel shirts and field shirts are the best I've ever owned, as are their worker wool pants, and they have enough merino clothing to layer for any weather.
Aside from the own brands, they often get very good surplus winter gear in, like thick Swiss knitted wool sweaters, Czech parkas, Finnish wool pants and so on.
My current winter outerwear workhorses are a Czech parka and a pair of Finnish M65 wool pants, total cost less than €50. With long johns and a woolen sweater underneath, I have yet to encounter winter weather that would make me uncomfortable.
I don't think of this as a technology or expensive, though. They are somewhat pricey, but can be worn for many winters and thus have good value.
If you have Decathlon nearby, start with them and ramp up as needed.
I don't like puffy winter jackets so I wear a long wool coat instead.
The difference in comfort is such that I barely feel any kind of fatigue or depression that the cold temperatures used to put on me.
It has changed my perception of winter and I couldn't have spent my money any better.
This is a costly investment though, be warned.
For the curious, the keyword that started it all: "layered clothing" and "layering".